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Cucumbers

Cucumbers are scientifically known as Cucumis sativus and belong to the same botanical family as melons (including watermelon and cantaloupe) and squashes (including summer squash, winter squash, zucchini and pumpkin). Commercial production of cucumbers is usually divided into two types. "Slicing cucumbers" are produced for fresh consumption. "Pickling cucumbers" are produced for eventual processing into pickles. Slicing cucumbers are usually larger and have thicker skins, while pickling cucumbers are usually smaller and have thinner skins.

What's New and Beneficial About Cucumbers

Fresh cucumbers are a somewhat unusual food when it comes to our eating habits since we are accustomed to enjoying them without removal of their seeds. This custom is an outstanding one in terms of its health benefits! Cucumber seeds contain a wide variety of phytonutrients, including both carotenoids and flavonoids. In one recent study, a small group of participants with mildly elevated blood fats consumed dried cucumber seed extracts on a daily basis over a period of six weeks. Results from this study included a variety of positive outcomes. Participants experienced decreased total cholesterol, decreased LDL cholesterol, decreased triglycerides, and increased HDL cholesterol. Of course, eating fresh cucumbers with their seeds intact is different than consuming dried cucumber seed extract. However, since the study participants consumed 500 milligrams of dried cucumber seed extract during the study, and since a dried cucumber seed (mature and large in size) weighs approximately 25 milligrams, we're talking about the equivalent of a relatively small number of seeds. So from a practical standpoint, this health-supportive amount of cucumber seeds seems easy enough to obtain from enjoyment of fresh cucumbers. We suspect that our website serving size of 1 cup (the equivalent of 1 small diced cucumber) would typically approximate this amount.

While still in its early stages (and mostly based on animal studies), research on cucumbers has been focusing more and more on alleviation of problems related to blood sugar regulation. When our blood sugar levels remain too high over a long period of time, one commonly developing problem is excessive production of reactive oxygen species (ROS) and reactive carbonyl species (RCS) that can damage cell structures and body components. Increased intake of cucumber holds promise as a step for significantly lessening this overproduction of ROS and RCS. Researchers believe that a wide variety of phenolic compounds in cucumbers are likely to be involved in this potential health benefit, including its many flavonoids and triterpenes.

Fermented foods - a staple in human cuisines since the very first civilizations - have become increasingly popular in the marketplace and included among many sought-after choices are fermented cucumbers. Though labeled as "pickles," cucumbers sold as pickles in the grocery have often not been fermented. Instead, they have been submerged in a very acidic liquid (usually vinegar). By contrast, fermented pickles are typically made by combining cucumbers with water, salt, and bacteria and giving the bacteria the right amount of time convert various substances in the cucumbers into different compounds. Studies on intake of fermented foods show a variety of potential health benefits, especially for the digestive tract. If you enjoy cucumbers in their pickled form, we encourage the selection of pickles that have been fermented. These types of pickles are usually easy to spot because the word "fermented" appears on the label.

While cucumbers are not as famous in the health world as some of their fellow vegetables (like cruciferous vegetables), it would be wrong to underestimate their health benefits and especially their phytonutrient content. While best studied in cruciferous vegetables, recent studies have identified the presence of several key lignans in cucumbers that had been more prominently associated with cruciferous vegetables (like broccoli) or allium vegetables (like onions or garlic). We now know that cucumber lignans include lariciresinol, pinoresinol, and secoisolariciresinol. Similarly, cucumbers are now known to contain phytonutrients that are members of the terpenoid family including cucurbitacins A, B, C, D, and E. All of the above phytonutrients have the potential to lower risk of oxidative stress and chronic inflammation. Decreased risk in these areas is also associated with decreased risk of multiple chronic diseases, and especially risk of certain cardiovascular diseases and certain cancers.

WHFoods Recommendations

Our outstanding level of green vegetable intake at WHFoods is 8 servings of green vegetables per day. A variety of days in our World's Healthiest Foods Meal Plan provide this outstanding amount, without compromising the delicious balance of textures and flavors in our World's Healthiest Foods Meal Plan Recipes. The many different types of green vegetables available to provide you with exceptional nourishment are nothing short of astonishing! Not only can you choose from dark green leafy vegetables from the cruciferous group (for example, mustard greens, turnip greens, kale, or collards), but also from the parsley/umbelliferous group (like fennel and celery), the allium vegetable group (including leeks) green lettuces like romaine, and of course from the squash/gourd family that includes cucumbers. Rather than relying exclusively on any one of these green vegetable subgroups, we recommend that you consider including green vegetables across all of these subgroups when putting together your weekly meal plan.

This chart graphically details the %DV that a serving of Cucumbers provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Cucumbers can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Cucumbers, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

Health Benefits

Broad-Spectrum Nutrient Richness from Cucumbers

Cucumbers have not received as much press as other vegetables in terms of their overall nutrient richness, but this long-beloved food provides us with a unique combination of conventional nutrients and phytonutrients. In terms of conventional nutrients, we are talking about a food that rises high in our WHFoods rating system with two excellents (for vitamin K and the mineral molybdenum), one very good (for the B vitamin, pantothenic acid), and 8 goods (for vitamin C, vitamin B1, and biotin in the vitamin category and for copper, magnesium, manganese, phosphorus, and potassium in the mineral category).

But the nutrient richness of cucumbers may be especially surprising when it comes to phytonutrients. Researchers have now identified 73 different phenolic compounds in cucumbers that are likely to provide us with antioxidant and anti-inflammatory benefits! The bulk of the research on cucumber phytonutrients focuses on three specific categories: flavonoids, lignans, and terpenoids. Below is a summary list of key phytonutrients in these three categories.

Flavonoids

apigenin

diosmetin

fisetin

luleolin

quercetin

kaempferol

luteolin

naringenin

theaflavanoside I

vicenin

Lignans

pinoresinol

lariciresinol

secoisolariciresinol

Triterpenes

cucurbitacin A

cucurbitacin B

cucurbitacin C

cucurbitacin D

Details about the best-researched health benefits of cucumbers are provided in the paragraphs below.

Antioxidant & Anti-Inflammatory Benefits of Cucumbers

Among all of the phytonutrients listed above, the vast majority have been shown to have antioxidant and/or anti-inflammatory properties either directly or through their influence on enzymes or metabolic pathways. For example, cucumber extracts inhibit the activity of cyclo-oxygenase 2 (COX-2), a well-studied pro-inflammatory enzyme. The activity of antioxidant enzymes - including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH) - has also been show to increase in the bloodstream of participants who consumed cucumber power. Cucumbers also contain fisetin - a flavonoid that has been of special interest to researchers not only because of its antioxidant and anti-inflammatory properties but also because of its potential for risk reduction in the case of certain cancer types. While cucumbers contain fisetin in a lower concentration than onions, strawberries, apples, or grapes, they are still an important source of this flavonoid.

The antioxidant benefits of cucumbers have also been studied in the context of type 2 diabetes. The metabolism of individuals diagnosed with type 2 diabetes can sometimes become subject to changes that involve excessive formation of reactive molecules in certain cells. Reactive oxygen species (ROS) and reactive carbonyl species (RCS) are two such molecules that can be formed in excessive amounts. Several recent studies have shown the ability of cucumbers to help reduce production of ROS and RCS.

While still in its early stages (and mostly based on animal studies), research on cucumbers has been focusing more and more on alleviation of problems related to blood sugar regulation. When our blood sugar levels remain too high over a long period of time, we see increases in ROS and RCS that can damage cell structures and body components. Increased intake of cucumber holds promise as a step for significantly lessening this overproduction of ROS and RCS. Researchers believe that a wide variety of phenolic compounds in cucumbers are likely to be involved in this potential health benefit, including its many flavonoids and terpenoids.

Other Potential Health Benefits from Cucumbers

Most of the research that we have seen on cucumbers and chronic disease risk have focused cardiovascular system problems, type 2 diabetes, and development of cancer. In all three areas, we consider the research to be preliminary, and much of it has been based on animal studies. There are logical theoretical connections between a food like cucumber that is rich in antioxidant and anti-inflammatory phytonutrients and risk of problems in each of the areas described above. In addition, specific phytonutrients in cucumbers have been tested in small-scale human studies and found to provide some of the health benefits described above.

Two examples in the area of cancer research are especially interesting. Scientists now know that cucumber lignans like lariciresinol, pinoresinol, and secoisolariciresinol can be converted by bacteria in our digestive tract into enterolignans like enterodiol and enterolactone. These enterolignans can bind onto estrogen receptors where they can have both pro-estrogenic and anti-estrogenic effects. In some preliminary studies, decreased risk of estrogen-related cancers - including certain cancers of the breast, ovary, uterus, and prostate - has been associated with intake of dietary lignans from a variety of different plant foods, including cucumber.

As a second example, cucumbers contain phytonutrients that are members of the terpenoid family called curcurbitacins. Cucumbers provide us with cucurbitacins A, B, C, D, and E. Researchers have determined that several different signaling pathways (for example, the JAK-STAT and MAPK pathways) associated with cancer cell development and cancer cell survival can be inhibited through the activity of cucurbitacins. Eventually, we hope to see human studies that confirm these risk-reducing benefits of cucumbers when they are consumed in a normal, everyday meal plan.

The cardiovascular benefits of cucumbers seem to involve two basic processes. First is protection of the blood vessel walls and blood constituents from oxygen-related damage. The 73 different phenolic phytonutrients identified in cucumbers - and especially its impressive array of flavonoids - appear to be central in providing this antioxidant protection. Second is the favorable impact of cucumber intake on blood fat levels, especially in individuals who have elevated blood fats. In one recent study, a small group of participants with mildly elevated blood fats consumed dried cucumber seed extracts on a daily basis over a period of six weeks and experienced a number of favorable changes in their blood fat levels. These changes included decreased total cholesterol, decreased LDL cholesterol, decreased triglycerides, and increased HDL cholesterol. We're reminded by this study not only to enjoy cucumbers for the health benefits, but to make sure and include their seeds.

In several recent studies, cucumber have been referred to as an "anti-diabetic" food, although we have yet to see a large-scale human study showing lower risk of type 2 diabetes in study participants who included cucumbers in their meal plans than in study participants who did not include this vegetable. However, what we have seen are studies showing improvement in certain metabolic problems experienced by persons with type 2 diabetes when they consumed cucumber extracts. These metabolic problems were primarily related to oxidative stress and excessive production of reactive oxygen species (ROS). Given their rich supply of antioxidant nutrients, it's not surprising to see cucumber intake resulting in this kind of improvement.

In this category of problems involving blood sugar regulation, it has also been interesting to see animal studies on fisetin - a flavonoid contained in select fruits and vegetables including cucumber. Enzymes that are need to make sugar within our liver cells (called gluconeogenic enzymes) appear to be inhibited in the presence of fisetin, thus suggesting a potential role for fisetin-containing foods (like cucumber) in support of blood sugar regulation.

Description

Even though long, dark green, smooth-skinned garden cucumbers are familiar vegetables in the produce sections of most groceries, cucumbers actually come in a wide variety of colors, sizes, shapes and textures. You may find white, yellow, and even orange-colored cucumbers, and they may be short, slightly oval, or even round in shape. Their skins can be smooth and thin, or thick and rough.

From a biological standpoint, cucumbers are actually fruits, not vegetables. (Fruits are parts of flowering plants that come from the ovary.) But we've become accustomed to thinking and referring to cucumbers as vegetables, and we include them in the vegetable group on our website.

In the U.S., fresh cucumbers are graded on their size, shape, color, and overall quality. Names for most grades that are commonly found in the produce section include U.S. Fancy, U.S. Extra #1, and U.S. #1. Cucumbers with these grades must be at least 6 inches in length, and have diameters no larger than 2-3/8 inches.

All cucumbers belong to the botanical plant family called Curcubitaceae. This family of plants includes melons and squashes. The cucumbers we're most familiar with in the grocery store belong to the specific genus/species group, Cucumis sativus.

While there are literally hundreds of different varieties of Cucumis sativus, virtually all can be divided into two basic types: slicing and pickling. Slicing cucumbers include all varieties that are cultivated for consumption in fresh form. In the United States, commonly planted varieties of slicing cucumber include Dasher, Conquistador, Slicemaster, Victory, Comet, Burpee Hybrid, and Sprint. These varieties tend to be fairly large in size and thick-skinned. Their size makes them easier for slicing, and their thick skin makes them easier to transport in whole food form without damage. (In many other countries, however, slicing cucumbers may be smaller in size and may be much more thinly skinned.)

Pickling cucumbers include all varieties that are cultivated not for consumption in fresh form, but for processing into pickles. In the United States, commonly planted varieties of pickling cucumber include Royal, Calypso, Pioneer, Bounty, Regal, Duke, and Blitz. Some of these pickling varieties are black-spine types (in reference to the texture of their outer skin) and some are white-spine. While pickling cucumbers can always be eaten fresh, their smaller size and generally thinner skins make them easier to ferment and preserve/jar.

Pickling is a process than can be used for many different foods. It's not limited to cucumbers and or even to the vegetable food group. In general, the word "pickling" refers to a method of preventing food spoilage that involves soaking in a liquid and/or fermenting.

While the language used to describe pickles can be very confusing, there are only two basic types of pickles: fermented and non-fermented. At WHFoods, we recommend selection of pickles that have been fermented because a good number of studies show potential health benefits from fermented foods, especially when it comes to the digestive tract. Fermenting is a process in which fresh foods (in this case cucumbers) are allowed to soak in a solution along with deliberately added microorganisms. The microorganisms - usually bacteria - are able to transform many substances in the food and bring about changes in its nutrient composition, texture, and flavor. Among these changes is a build-up of acids that help protect the food (in this case cucumbers) from spoilage. With proper fermentation, fresh foods like cucumbers can be transformed in a way that greatly increases their shelf life and simultaneously creates new compounds with potential health benefits. In short: there is research to support the value of fermented foods in a meal plan (even though we do yet have studies specific to cucumbers that compare the fermented to non-fermented versions). Fermented pickles are usually easy to spot because in addition to the words "pickled" and "cucumber," the word "fermented" also appears on the label.

Cucumbers are typically fermented in brine (water that's been highly saturated in salt). In fact, the word "pickle" actually comes from the Dutch "pekel" meaning "brine." Alongside of salt, pickling brines may contain other ingredients, including vinegar, dill seed, garlic, and lime (calcium hydroxide or calcium oxide). "Dill pickles" get their name from the addition of dill seed to the brine. "Kosher dills" are brined not only with dill, but also with garlic. (One additional note with respect to marketplace labeling: when you see the term, "kosher dills," it does not necessarily mean that the pickled cucumbers were prepared according to kosher dietary laws. The word "kosher" in their name often refers to a general style of preparation in which a good bit of garlic has been used in the brining process. If you are seeking pickles that have been prepared according to kosher dietary laws, look for "certified kosher" on the label, not just "kosher" or "kosher-style.")

Fermented pickles are often called "brined pickles," but this description can be confusing, as well. These two terms aren't truly interchangeable since some brined pickles are "quick brined" and haven't been given time for fermentation. When pickles are "quick brined," the brining solution usually contains a significant amount of vinegar, and this added vinegar is what prevents the pickles from spoiling, not a buildup of acids through microbial fermentation. Non-fermented pickles of all kinds—often referred to as "quick pickled"— usually rely on the addition of vinegar or another highly-acidic solution to prevent spoilage.

While genetically engineered cucumbers do exist, genetic engineering is not responsible for the existence of seedless varieties of cucumbers. Through a natural process called parthenogenesis, cucumber plants can fruit without pollen. In the absence of pollen, seeds do not develop in the fruit. While some people have a personal preference for seedless cucumbers, it's worth remembering that cucumber seeds are rich source of phytonutrients that may not be found in anywhere close to the same amount in the skin or flesh.

Sometimes you will hear the word "gherkin" being used to refer to cucumbers and pickles. This word can be used to describe a variety of cucumber that comes from the same plant species (Cucumis sativus) that is the source of most other cucumber varieties found in the grocery. But the term "gherkin" can also be used to describe a cucumber variety that comes from a different species of plant (Cucumis anguiria).

History

Cucumber plants naturally thrive in both temperate and tropical environments, and for this reason have been widely cultivated worldwide. Historically, they appear to have originated in Asia, in parts of China with temperate climates (for example, Guangxi, Guizhou, and Yunnan) and in Asian regions with more tropical climates like the southern regions of India, Sri Lanka, Myanmar, and Thailand. Cucumbers have also naturalized to several regions of the world. At present, China is by far the world's largest producer of cucumbers with over 54 million tons of total production. Turkey, Iran, the Russian Federation, Ukraine, and Spain are the next four highest producers, followed by the United States, Mexico, and Egypt.

Within the United States, Florida, Michigan, North Carolina, Ohio, and Texas are the top cucumber-producing states. Approximately 50,000 acres of cucumbers grown for fresh consumption and 100,000 acres of cucumbers grown for pickling are planted in the U.S. each year. In addition to these field-planted acres is additional production of greenhouse cucumbers in a much smaller amount (less than 10% of the total planted fields). Demand for cucumbers from U.S. consumers means that a greater amount of this much-loved vegetable gets imported into the U.S. - primarily from Mexico - than gets produced domestically.

How to Select and Store

Since cucumbers can be very sensitive to heat, you'll be on safer ground if you choose those that are displayed in refrigerated cases in the market. They should be firm, rounded at their edges, and their color should be a bright medium to dark green. Avoid cucumbers that are yellow, puffy, have sunken water-soaked areas, or are wrinkled at their tips.

We address the issue of seeds and skins in our "Tips for Preparing Cucumbers" section below. But during the selection process, you may find it helpful to know that thick-skinned cucumbers will generally have more seeds (with thin-skinned cucumbers having fewer seeds).

At WHFoods, we encourage the purchase of certified organically grown foods, and cucumbers are no exception. Repeated research studies on organic foods as a group show that your likelihood of exposure to contaminants such as pesticides and heavy metals can be greatly reduced through the purchased of certified organic foods, including cucumbers. In many cases, you may be able to find a local organic grower who sells cucumbers but has not applied for formal organic certification either through the U.S. Department of Agriculture (USDA) or through a state agency. (Examples of states offering state-certified organic foods include California, New York, Oregon, Vermont, and Washington.) However, if you are shopping in a large supermarket, your most reliable source of organically grown cucumbers is very likely to be cucumbers that display the USDA organic logo.

Cucumbers should be stored in the refrigerator where they will keep for several days. Cucumbers should not be left out at room temperature for too long as this may cause them to wilt and become limp.

Here is some background on why we recommend refrigerating cucumbers. Whenever food is stored, four basic factors affect its nutrient composition: exposure to air, exposure to light, exposure to heat, and length of time in storage. Vitamin C, vitamin B6, and carotenoids are good examples of nutrients highly susceptible to heat damage, and for this reason, their loss from food is very likely to be slowed down through refrigeration.

If you do not use the entire cucumber during one meal, place the remainder in a tightly sealed container so that it does not dry out. From the standpoint of overall quality, cucumber should be used within one or two days.

Tips for Preparing and Cooking

We are often asked whether it's best to remove the skins and seeds of cucumbers before eating or whether it's best to leave them intact. Because both of these cucumber parts are nutrient-rich, with each containing unique phytonutrients of its own, we recommend that cucumbers be left intact when slicing or dicing.

Many cucumbers are waxed prior to sale. However, it is not always possible to tell with the naked eye whether a glossy-skinned cucumber has been waxed or not, since some cucumbers naturally produce their own wax-like skin. Cucumbers can be waxed with a variety of substances. Since there is a good bit of restriction on the types of added wax that can be used on certified organic cucumbers, selecting these cucumbers can be a good way of lowering your risk of exposure to potential undesirable substances in the wax. These substances sometimes result from the processing and purification of petroleum-based, food-grade waxes.

Regardless of the type of cucumber that you select - organic or non-organic, waxed or unwaxed - we recommend thorough washing of the whole cucumber under cool running water while scrubbing with a natural bristle brush. And if you decide to select non-organic cucumbers (that are either waxed or unwaxed), we still recommend consumption of the skin, even though we don't have a sound research basis for making this recommendation. Still, our overall understanding of nutrition, health, and contaminant residues on food makes us think that the nutrient richness of the cucumber skin has more of an "upside" in terms of potential health benefits than the "downside" of potential contaminant residues. In addition, of course, thorough rinsing and gentle scrubbing should help to remove some potentially unwanted contaminants.

If you'd like even more recipes and ways to prepare cucumbers the Nutrient-Rich Way, you may want to explore The World's Healthiest Foods book.

Nutritional Profile

Cucumbers provide us with a variety of health-supportive phytonutrients. Included among these phytonutrients are flavonoids (like apigenin, fisetin, kaempferol, luteolin, quercetin, and vicenin), lignans (pinoresinol, lariciresinol, and secoisolariciresinol), and triterpenes (cucurbitacins A, B, C and D).

Cucumbers are an excellent source of vitamin K and molybdenum. They are also a very good source of the pantothenic acid. They are also a good source of copper, potassium, manganese, vitamin C, phosphorus, magnesium, biotin and vitamin B1.

Introduction to Food Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn't contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food's in-depth nutritional profile that includes values for dozens of nutrients - not just the ones rated as excellent, very good, or good - please use the link below the chart.) To read this chart accurately, you'll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food's nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling."
Read more background information and details of our rating system.

In-Depth Nutritional Profile

In addition to the nutrients highlighted in our ratings chart, here is an
in-depth nutritional profile for Cucumbers. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.

Note:

The nutrient profiles provided in this website are derived from The Food Processor, Version 10.12.0, ESHA Research, Salem, Oregon, USA. Among the 50,000+ food items in the master database and 163 nutritional components per item, specific nutrient values were frequently missing from any particular food item. We chose the designation "--" to represent those nutrients for which no value was included in this version of the database.

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For education only, consult a healthcare practitioner for any health problems.

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